Field of the Invention
The present invention relates to an image blur correction device provided in a lens barrel of an image pickup apparatus, such as a digital camera, a lens barrel provided with the image blur correction device, and an image pickup apparatus.
Description of the Related Art
Among image pickup apparatuses, such as a digital camera, there is one provided with a mechanism for correcting image blur by moving part of an optical system or an image pickup device on a plane orthogonal to an optical axis direction according to a camera shake amount, so as to prevent an object image from being blurred e.g. by a camera shake occurring during shooting.
For example, in Japanese Patent Laid Open Publication No. 2008-220031, there has been disclosed an image blur correction device that moves an image pickup device by a so-called vibratory wave motor on a plane orthogonal to an optical axis direction to thereby correct image blur. The vibratory wave motor used in the image blur correction device disclosed in Japanese Patent Laid-Open. Publication No. 2008-220031 is provided with a vibrator having two protrusions, and causes the extremities of the respective two protrusions to perform elliptic motion to thereby drive a driven element held in pressure contact with the two protrusions in one direction.
More specifically, when directions orthogonal to each other on the plane orthogonal to the optical axis are defined as an X direction and a Y direction, the image blur correction device disclosed in Japanese Patent Laid-Open Publication No. 2008-220031 is provided with an X frame that can move in the Y direction while holding the image pickup device and a fixed member that supports the X frame such that the X frame can be moved in the X direction. The fixed member is formed with a first vibrator for driving the X frame in the X direction, and the X frame is formed with a second vibrator for driving the image pickup device in the Y direction. This makes it possible to move the image pickup device in the X and Y directions and restrict rotation of the image pickup device about the optical axis at the same time.
However, the image blur correction device disclosed in Japanese Patent Laid-Open Publication No. 2008-220031 uses the frame members that can be moved in the X and Y directions, respectively. Therefore, the image blur correction device is large in the number of components and complicated in construction. To solve this problem, it can be envisaged to simplify the construction of the image blur correction device by eliminating the X frame such that the image pickup device is directly driven using a vibrator for driving in the X direction and another vibrator for driving in the Y direction. In this case, however, when one vibrator is driven, a frictional holding force is generated by the other vibrator. For this reason, a moment of force for causing rotation of the image pickup device is generated, which causes undesired rotation of the image pickup device. This brings about a problem that the image quality of a photographed image is degraded.